1. Field of Endeavor
The present invention relates to a countermeasure system against sensor-guided threats and more particularly to a broadband laser countermeasure system against sensor-guided threats.
2. State of Technology
U.S. Pat. No. 5,703,314 to Delbert Brent Meeker for an infrared projector countermeasure system patented Dec. 30, 1997 provides the following state of technology information, “It is well known that current state of the art missiles have the capability of homing on targets, such as enemy aircraft, ships or other targets, which emit infrared energy. Generally, these missiles employ imaging seekers, which sense the infrared energy from the target, to track and then destroy the target. Generally, infrared radiation emitting decoy projectiles are used to deceive an incoming missile as to the location and heading of the target. These decoy projectiles are, for example, carried on targets such as aircraft or ships so that when the target's detection instruments detect the approach of an incoming missile equipped with an infrared search system a decoy projectile can be fired into the air. Subsequently, at a predetermined height and distance from the target, the decoy projectile will ignite and eject combustible flakes which burn and emit infrared radiation. These combustible flakes from the decoy form a burning interference cloud which descends slowly toward the earth's surface diverting the incoming missile toward the interference cloud and away from the target. Modern, imaging infrared seekers can distinguish between a localized, point source of radiation provided by a flare and the distributed, complex radiation pattern of an aircraft structure. This capability is one of the reasons for using an imaging infrared seeker on a missile when tracking an aircraft. When protection of very rapidly moving targets is involved, state of the art imaging infrared seekers used in missiles scan for multiple frequencies in the infrared region of the electromagnetic spectrum. This renders the decoy projectiles ineffective since the interference cloud generated by the projectiles or even a flare generally have a characteristic frequency spectrum which can be distinguished from that of an aircraft.”
U.S. Pat. No. 6,196,497 to Simon Lankes et al. for an infrared seeker head for target seeking missile patented Mar. 6, 2001 provides the following state of technology information, “To defend against attacking target seeking missile, measures are taken by an attacked aircraft for causing interference in the infrared seeker head. Prior art infrared seeker heads for guided missiles usually have analog signal processing and use a reticle. To deceive the signal processing of such seeker heads, it is sufficient if a suitably modulated infrared radiation source, (infrared jammer) emits interfering radiation at the target site. This radiation source may be a laser with large beam divergence, or a plasma lamp, as a relatively small radiation level is sufficient to cause interference. Modern picture processing infrared seeker heads are no longer as easily deceived. An interference could be achieved, in which the laser radiation is focused on the approaching missile. Then by dazzling and even destruction of the infrared detector, the guidance of the missile could be totally interrupted and the missile would miss the thus protected target.”
U.S. Pat. No. 6,324,955 for an explosive countermeasure device patented Dec. 4, 2001 provides the following state of technology information, “Anti-aircraft missiles have electro-optical seeker devices for homing in on the infrared or other wavelength radiation emitted from an aircraft engine tailpipe. Conventional flares are often used in attempting to decoy the seeker devices so that they lose their lock on the target, the aircraft being flown out of line of sight with the missile under the cover of the decoy flare. In conventional pyrotechnic flares, a mixture of chemicals contained in a cartridge is ignited after expelling the flare from the aircraft, forming an infrared source for decoying a hostile infrared seeking missile. The duration of such flares is from milliseconds to seconds in length. Such devices are quite well known and understood, and missile designers have developed means for enabling current missiles to ignore most of the existing flare countermeasures.”
U.S. Pat. No. 6,410,897 to Mary Dominique O'Neill for a method and apparatus for aircraft protection against missile threats patented Jun. 25, 2002 provides the following state of technology information, “Missiles fired at aircraft are usually guided either by a light seeker or by radar. Of the various types of seekers, infrared light seekers pose some of the greatest problems to aircraft defense. Unlike radar seekers, infrared seekers are passive and do not emit a detectable signal prior to the firing of the missile. Pilots therefore have little warning of their presence prior to the firing of the missile. Infrared-guided missile systems are relatively inexpensive, and human-portable units are widely available. There has been a continuing effort to develop sensor systems and countermeasures that are carried on aircraft and are used to detect missile threats, particularly infrared-guided missiles, and take action against the missile threats. The sensor system must be effective to detect the infrared signature of a relatively small-sized missile at as great a distance as possible, in order to allow time for the countermeasure to be effective. In one approach, a wide-angle, two-color staring sensor system has been suggested to be particularly effective in detecting threats. This approach is limited by its low resolution and thence its ability to detect potential targets at great distances and susceptibility to smearing of the image, as well as the incomplete status of the detector technology. Additionally, the detection and warning components of the system must be integrated with the countermeasures components of the system.”
U.S. Pat. No. 6,055,909 to Ray L. Sweeny for “Electronically Configurable Towed Decoy for Dispensing Infrared Emitting Flares,” patented May 2, 2000 provides the following state of technology information, “Infrared-guided and radar-guided missiles pose the primary threats to military aircraft engaged in a combat environment. These missiles use their radar and IR guidance to home in on aircraft, thereby substantially increasing their probability of a ‘hit.’ Current military aircraft are particularly vulnerable to attack from IR-guided surface-to-air and air-to-air missiles. Statistics gathered from analysis of aircraft losses in hostile actions since 1980 show that almost 90% of these losses have been the result of IR-guided missile attacks. Thus, IR-guided missiles have become a formidable threat to military aircraft. These missiles can either be guided to their target entirely using IR-guidance or can initially utilize radar guidance and then switch over to IR guidance as they come into closer proximity to the target. In regards to the latter approach, IR-guided missiles can be cued via radar, or a passive Infrared Search and Track (IRST) system employed with the missiles can be alerted and properly oriented via a data link from a ground based surveillance or early warning radar. Optimally, however, IR-guided missiles are launched at an aircraft without the use of radar cueing, which often alerts an aircrew to an impending missile attack when the radar signals are detected by an on-board radar warning receiver. These IR-guidance only missiles are essentially passive and can be launched as a result of visual observation of the approaching aircraft, via self cueing or with assistance from an IRST system. In the absence of warning to the target aircraft, these missiles have a high degree of lethality.”
U.S. Pat. No. 6,662,700 to Mary Dominique O'Neill for “Method for Protecting an Aircraft Against a Threat that Utilizes an Infrared Sensor,” patented Dec. 16, 2003 provides the following state of technology information, “Threats against military aircraft, such as air-launched or ground-launched missiles, are typically guided by a radar sensor, an infrared sensor, or both. Radar sensors are highly accurate in identifying and locating their targets. They have the disadvantage that they are active devices that emit radar signals, and their emissions may be detected by the target and used to evade or to launch a counter-attack against the radar source. Infrared sensors, on the other hand, are passive devices that do not reveal their presence or operation. The great majority of aircraft losses to hostile attacks over the past 20 years have been to infrared-guided missiles. In most cases, the pilots of the aircraft that were shot down were not aware that they were under attack until the infrared-guided missile detonated. Infrared-guided missiles have the disadvantage that they typically must be initially positioned much more closely to their potential targets in order for the infrared sensor of the missile to be effective, as compared with a radar-guided missile. The fields of view of the infrared sensors are usually quite narrow, on the order of a few degrees. In most cases, the infrared sensor must therefore acquire its potential target prior to launch of the missile and remain ‘locked onto’ the target for the entire time from launch until intercept. If the acquisition is lost during the flight of the missile, it is usually impossible to re-acquire the target without using an active sensor that warns the target of its presence. There are a number of countermeasures to defeat infrared-guided missiles. Historically, the most common countermeasure has been the use of flares that produce false signals to confuse the infrared sensor. The current generation of infrared-guided missiles utilizes counter-countermeasures programmed to ignore flares, based upon distinguishing features of the flares such as their different motion than the previously acquired target and/or their different heat-emitting properties as compared with the previously acquired target. Lamps and directional lasers may be used to blind or confuse the infrared sensor, but these approaches have drawbacks in respect to size, weight, complexity, and power requirements.”